As well as creating diagrams, Diagrammr allows you to embed them, providing an image/PNG URI for your diagram; you can also edit the image (that is, edit the script that generates the image) after the fact via a shareable URI.

The URI for the editor page can be generated from the image URI, though, so without the ability to set a password on the editor page when you first crate a new image, this means that any time you embed a Diagrammr image, someone else could go and edit the image?

In an educational context, tools like this make it much easier for students to create their own diagrams (typing in a graph description is far quicker than trying to lay it out by hand in a drawing package). As you script the diagram, your attention is focussed on the local structural components/relations that define the graph, whilst at the same time the automatically generated diagram visualises the overall structure and brings alive its complexity at the network level.

(I’m not sure how the graph layouts are generated – maybe using Graphviz on the server to generate the image and return it to the browser? If so, an improved version of diagrammr might be able to return the compiled xdot version of the graph back to an interactive canviz component running in the browser?)

If you’re working in an insitutional VLE context, where the powers that be are still trying to retain control of everything, the Canviz component might offer one solution – an HTML 5 canvas library for displaying ‘compiled’ Graphviz network descriptions.